U.S. patent number 7,518,093 [Application Number 11/176,677] was granted by the patent office on 2009-04-14 for vehicle window with de-icing feature and method.
This patent grant is currently assigned to Guardian Industries Corp.. Invention is credited to Daniel F Prone, Scott V. Thomsen, Vijayen S. Veerasamy.
United States Patent |
7,518,093 |
Veerasamy , et al. |
April 14, 2009 |
Vehicle window with de-icing feature and method
Abstract
A window such as a vehicle window (e.g., windshield) has a
de-icing feature. In certain example embodiments, a conductive
structure is provided on an interior surface of a substrate of the
window, AC tuned to an ice removal frequency is caused to run
through the conductive structure, and fields generated by the AC
passing through the conductive structure propagate through the
substrate to an exterior surface of the window and can be absorbed
by ice thereby causing the ice to melt and/or be removed from the
window.
Inventors: |
Veerasamy; Vijayen S. (Ann
Arbor, MI), Prone; Daniel F (Trenton, MI), Thomsen; Scott
V. (South Lyon, MI) |
Assignee: |
Guardian Industries Corp.
(Auburn Hills, MI)
|
Family
ID: |
37617372 |
Appl.
No.: |
11/176,677 |
Filed: |
July 8, 2005 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20070007284 A1 |
Jan 11, 2007 |
|
Current U.S.
Class: |
219/772; 219/773;
219/203 |
Current CPC
Class: |
B32B
17/10036 (20130101); H05B 3/86 (20130101); B32B
17/10761 (20130101); B32B 17/10385 (20130101); H05B
3/84 (20130101); H05B 2203/016 (20130101) |
Current International
Class: |
H05B
6/62 (20060101); B60L 1/02 (20060101) |
Field of
Search: |
;219/764,773,203,772,628,687,202,219 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Robinson; Daniel L
Attorney, Agent or Firm: Nixon & Vanderhye P.C.
Claims
The invention claimed is:
1. A method of de-icing a vehicle windshield, the windshield
comprising an exterior glass substrate and an interior glass
substrate that are laminated to one another via at least a polymer
inclusive interlayer, the method comprising: providing at least one
conductor on an interior surface of the exterior glass substrate,
wherein the conductor comprises a continuous coating of a
transparent conductor; and applying AC at a frequency of from about
5 to 40 kHz to the conductor on the interior surface of the
exterior glass substrate, so that electromagnetic energy caused by
application of the AC to the conductor propagates through the
exterior glass substrate and is absorbed by ice on an exterior
surface of the vehicle windshield thereby causing the ice to melt
and/or be removed from the vehicle windshield.
2. The method of claim 1, wherein the AC is applied at a frequency
of from about 10 to 25 kHz.
3. The method of claim 1, wherein the AC is applied at a frequency
of from about 10 to 20 kHz.
4. The method of claim 1, wherein the conductor comprises silver
and/or indium tin oxide.
5. The method of claim 1, wherein the AC is applied to the
conductor on the interior surface of the exterior glass substrate,
and is also applied to a conductor on a surface of the interior
glass substrate.
6. The method of claim 1, wherein a de-icing circuit comprises the
conductor and at least one AC power source, and wherein impedance
of the circuit is tuned so that only when ice is present then the
circuit becomes lossy and dissipates energy to the ice, and
otherwise the circuit resonates.
7. A window including a de-icing structure, the window comprising:
an exterior substrate and an interior substrate spaced apart from
one another; at least one conductor provided on an interior surface
of the exterior substrate, wherein the conductor comprises a
continuous coating of a transparent conductor; and an AC power
source for applying AC at a frequency of from about 5 to 40 kHz to
the conductor on the interior surface of the exterior substrate so
that electromagnetic energy caused by application of the AC to the
conductor is coupled to ice on an exterior surface of the exterior
substrate thereby causing the ice to melt and/or be removed from
the window.
8. The window of claim 7, wherein the window is a vehicle
windshield.
9. The window of claim 7, wherein the AC power source applies AC at
a frequency of from about 10 to 25 kHz.
10. The window of claim 7, wherein the conductor comprises silver
and/or indium tin oxide.
11. The window of claim 7, wherein the AC is applied to the
conductor on the interior surface of the exterior substrate, and is
also applied to a conductor on a surface of the interior glass
substrate.
12. The window of claim 7, wherein the de-icing structure comprises
a de-icing circuit that comprises the conductor and the AC power
source, and wherein impedance of the circuit is tuned so that the
circuit becomes lossy when ice is present and dissipates energy to
the ice, and when ice and/or water is not present on the exterior
surface of the window the circuit resonates.
13. The method of claim 1, wherein at least one dielectric layer is
provided between the conductor and the interior surface of the
exterior glass substrate.
Description
This invention relates to a window, such as a vehicle window (e.g.,
windshield) having a de-icing features. In certain example
embodiments, a conductive structure is provided on an interior
surface of a substrate of the window, AC (Alternating Current)
tuned to an ice removal frequency is caused to run through the
conductive structure, and fields generated by AC passing through
the conductive structure propagate through the substrate to an
exterior surface of the window and can be absorbed by ice thereby
causing the ice to melt and/or be removed from the window.
BACKGROUND OF THE INVENTION
Ice tends to build up on the exterior surfaces of vehicle windows
in winter months. Ice build-up may be caused by snow, freezing
rain, sleet, or the like in different instances. Ice impairs a
vehicle driver's ability to adequately see through a vehicle window
such as a windshield. Thus, it would be desirable to provide
vehicle windows with an ice removal feature.
De-icing structures for vehicle windows are known in the art. For
example, see U.S. Pat. No. 6,027,075, the disclosure of which is
hereby incorporated herein by reference. Unfortunately, the
de-icing grid structure of the '075 patent is provided on the
exterior surface of the vehicle window, and thus is easily
susceptible to damage caused by the environment (e.g., corrosion
and/or physical damage). Moreover, exposed electrodes which may be
touched by persons are not desirable.
In view of the above, there exists a need in the art for a window
(e.g., vehicle window) that is provided with an ice-removal
structure or feature that is not entirely provided on the exterior
surface of the window.
BRIEF SUMMARY OF EXAMPLE EMBODIMENTS OF THE INVENTION
In certain example embodiments of this invention, a window such as
a vehicle window (e.g., windshield) is provided with a de-icing
feature/structure. In certain example embodiments, a conductive
structure such as one or more electrodes is provided on an interior
surface of a substrate of the window. Then, AC (Alternating
Current) tuned to an ice removal frequency is caused to run through
the conductive structure, and fields generated by the AC passing
through the conductive structure propagate through the substrate
(e.g., glass substrate of the window) to an exterior surface of the
window and can be absorbed by ice thereby causing the ice to melt
and/or be removed from the window. In other words, once the
de-icing circuit is driven with AC, electromagnetic energy from the
circuit is coupled to ice on the exterior surface of the window.
This electromagnetic energy is absorbed by the ice thereby causing
ice removal from the window.
In certain example embodiments, it has been found that an AC
frequency tuned to ice removal is from about 5-40 kHz, more
preferably from about 10-25 kHz, and most preferably from about
10-20 kHz. It has surprisingly been found that the use of AC at
this frequency causes generation of electromagnetic energy that is
most efficiently absorbed by ice on the exterior of the window,
thereby resulting in the most efficient ice removal. A sine wave
and/or square wave type of AC may be used in different example
embodiments of this invention.
In certain example embodiments of this invention, there is provided
a method of de-icing a vehicle windshield, the windshield
comprising an exterior glass substrate and an interior glass
substrate that are laminated to one another via at least a polymer
inclusive interlayer, the method comprising: providing at least one
conductor on an interior surface of the exterior glass substrate;
applying AC at a frequency of from about 5 to 40 kHz to the
conductor on the interior surface of the exterior glass substrate,
so that electromagnetic energy caused by application of the AC to
the conductor propagates through the exterior glass substrate and
is absorbed by ice on an exterior surface of the vehicle windshield
thereby causing the ice to melt and/or be removed from the vehicle
windshield.
In other example embodiments of this invention, there is provided a
window including a de-icing structure, the window comprising: an
exterior substrate and an interior substrate spaced apart from one
another; at least one conductor provided on an interior surface of
the exterior substrate; and an AC power source for applying AC at a
frequency of from about 5 to 40 kHz to the conductor on the
interior surface of the exterior substrate so that electromagnetic
energy caused by application of the AC to the conductor is coupled
to ice on an exterior surface of the exterior substrate thereby
causing the ice to melt and/or be removed from the window.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic diagram of a vehicle window (e.g.,
windshield) including a de-icing feature according to an example
embodiment of this invention.
FIG. 2 is a cross sectional view of the window of FIG. 1.
FIG. 3 is a cross sectional view of a window according to another
example embodiment of this invention.
FIG. 4 is a cross sectional view of a window according to another
example embodiment of this invention.
DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS THE INVENTION
Referring now more particularly to the accompanying drawings in
which like reference numerals indicate like parts throughout the
several views.
FIGS. 1-2 illustrate an example window (vehicle windshield in this
example case) according to an example embodiment of this invention,
where FIG. 1 is a schematic diagram and FIG. 2 is a cross sectional
view of the window of FIG. 1. The vehicle window of FIGS. 1-2
includes first and second opposed glass substrates 1 and 3 with a
polymer-based laminating interlayer (e.g., PVB or the like) 5
provided therebetween. Glass substrate 1 is the outer glass
substrate of the windshield located adjacent the exterior of the
vehicle, whereas glass substrate 3 is the interior glass substrate
of the windshield located adjacent the vehicle interior. The glass
substrates 1 and 3 may be perfectly flat, or bent, in different
example embodiments of this invention, and are often heat treated
(e.g., thermally tempered and/or heat strengthened). Windshield or
window may have a visible transmission of at least about 60%, more
preferably of at least about 70%, and sometimes at least 75%, in
certain example embodiments of this invention.
The ice removal structure of the FIG. 1-2 embodiment includes
comb-shaped conductors 11 and 12, which include conductive bus bars
11a and 12a, respectively. The comb-shaped conductors 11 and 12
further include conductive comb teeth 11b and 12b, respectively,
which extend across a viewing area of the window from the bus bars.
The conductors (or electrodes) 11 and 12 may be provided directly
on and contacting the surface of the glass substrate 1 in certain
example embodiments of this invention, although in alternative
embodiments other layers (e.g., dielectric layer or layers such as
silicon nitride or the like) may be provided between the substrate
1 and the conductors. In making up conductive grid G across a
central and/or viewing area of the window, moving from top to
bottom or vice versa across the window, the comb teeth 11b from the
conductor 11 alternate with the comb teeth 12b from the conductor
12 as shown in FIG. 1 in certain example embodiments of this
invention. Comb teeth 11b and 12b may be formed of any suitable
wiring material to make up a conductive grid G, with silver, gold,
or the like being example conductive materials. Conductors 11 and
12 may be formed of like materials, which may be the same or
different than their respective teeth portions. The gap between the
teeth of conductors 11 and 12 acts as a capacitor, and waves may
oscillate back and forth between the two comb-shaped
conductors.
In certain example embodiments, the conductors 11 and 12 may form a
capacitive part of the ice removal circuit. An inductor or choke
may be used to provide a resonant circuit with broad enough Q
factor. When ice 18 is present on the exterior surface of the
window the circuit picks up an extra resistive component with the
enhanced capacitive load of the ice. This allows energy to be
dissipated into the ice and permits the melting of the ice 18. Such
an ice mounting circuit may also contain an ice and/or water
sensing mechanism that may automatically allow energy to be
delivered from the power source 15 to the circuitry when ice and/or
water is detected as being present.
FIG. 2 illustrates that the conductive grid G formed by the
interspersed conductors (or electrodes) 11 and 12 is formed on the
interior surface 9 of glass substrate 1 (i.e., on the interior
surface of the exterior substrate 1). Thus, the conductive grid G
made up of conductors 11 and 12 is protected from the surrounding
environment exterior the vehicle by glass substrate 1, and is
protected from the environment inside the vehicle by interior glass
substrate 3 and polymer interlayer 5. Thus, the conductive grid G
cannot be easily damaged, and cannot be readily touched by persons
in or around the vehicle.
In certain example embodiments of this invention, a window such as
a the vehicle window (e.g., windshield) of FIGS. 1-2 is provided
with de-icing feature/structure including grid G including
conductors 11, 12 and AC power source 15 electrically connected to
the conductors 11, 12. The conductive structure including
electrodes 11 and 12 is provided on an interior surface 9 of glass
substrate 9. From AC power source 15, AC tuned to an ice removal
frequency is caused to run through the electrode(s) 11 and/or 12.
In accordance with the laws of physics (e.g., Maxwell's Equations),
the passing of the AC through the conductors 11, 12 causes
electromagnetic fields to be generated. The electromagnetic fields
generated by the AC passing through the conductive structure 11, 12
propagate through the glass substrate 1 and encompass and/or reach
an exterior surface 10 of the window and can be absorbed by ice 18
thereby causing the ice 18 to melt and/or be removed from the
window. Stated another way, once the de-icing circuit is driven
with AC, electromagnetic energy from the circuit is coupled to ice
18 on the exterior surface of the window. This electromagnetic
energy is absorbed by the ice 18 thereby causing ice removal from
the window via melting and/or delamination.
In certain example embodiments of this invention, the ice-removal
structure allows the impedance of the circuit to be tuned so that
only, or substantially only, when ice 18 is present the circuit
becomes lossy and dissipates energy to the ice; but otherwise the
circuit resonates. Thus, the circuit may be termed an ice-induced
lossy circuit which is not significantly lossy when ice 18 is not
present on the exterior surface of the window. This is advantageous
in that power consumption may be made more efficient.
In certain example embodiments, it has been found that an AC
frequency from the power source 15 tuned to ice removal is from
about 5-40 kHz, more preferably from about 10-25 kHz, and most
preferably from about 10-20 kHz. It has surprisingly been found
that the use of AC at this frequency causes generation of
electromagnetic energy that is most efficiently absorbed by ice 18
on the exterior surface 10 of the window, thereby resulting in the
most efficient ice removal. A sine wave and/or square wave type of
AC may be used in different example embodiments of this invention.
In certain example embodiments, a pulsing technique used may be the
so called chirping mode whereby a sinusoidal wave is modulated by
square pulses. In certain example embodiments, it has also been
found that application of such AC at about 300-500 V is
particularly effective at ice removal.
In certain example embodiments of this invention, the grid may be
formed by first depositing a continuous conductive layer of Ag, Cr,
Au, ITO, or the like on the glass substrate 1. The conductive layer
can then be laser scribed into the two conductors 11 and 12 with a
spatial frequency such that line widths (i.e., the width of comb
teeth 11b and/or 12b) may be no larger than about 200 .mu.m, more
preferably no larger than about 100 .mu.m, in certain example
embodiments. Such a gridded system would be difficult to be seen by
the naked eye and may even appear transparent to a vehicle operator
or one exterior the vehicle. In certain example embodiments, the
spacing "S" between adjacent approximately parallel conductive grid
members 11b and 12b may be from about 100 to 800 .mu.m, more
preferably from about 100 to 500 .mu.m, and sometimes from about
125 to 250 .mu.m.
FIG. 3 is a cross sectional view of a window (e.g., windshield)
according to another example embodiment of this invention, having a
de-icing structure and circuit. The FIG. 3 embodiment is the same
as the FIG. 1-2 embodiment discussed above, except that the grid G
of the FIG. 1-2 embodiment is replaced in the FIG. 3 embodiment
with a continuous conductive sheet or blanket 20 of a transparent
conductive oxide such as indium tin oxide (ITO) or the like. A
transparent silver or silver based coating could also be used as
the heating conductive coating 20 in alternative example
embodiments of this invention. In certain example instances, the
conductive coating 20 may be a silver based IR reflecting layer of
a low-E coating. The same AC at the frequency discussed above is
used and applied to the transparent conductive coating 20. In
certain example embodiments, the AC is applied across the
conductive coating 20 using a pair of bus bars or the like. Heat
and/or electromagnetic waves resulting from the AC passing through
conductive coating 20 propagate through glass substrate 1 and
is/are absorbed by ice 18 thereby causing the ice to melt and/or
delaminate from the window structure.
FIG. 4 is a cross sectional view of a window (e.g., windshield)
according to another example embodiment of this invention, having a
de-icing structure and circuit. The FIG. 4 embodiment is the same
as the FIG. 1-2 embodiment discussed above, except that an
additional continuous conductive sheet or blanket 20 of a
transparent conductive oxide such as indium tin oxide (ITO) or the
like is provided on the interior surface of the other glass
substrate 3. Also, in the FIG. 4 embodiment, the grid G is made up
of one conductor and not two spaced apart combs. AC is applied so
that one terminal of the AC power source 15 is electrically
connected to grid 6 (of a single electrically connected
conductor--not two spaced apart combs in this example embodiment)
and the other terminal of the power source 15 is electrically
connected to the conductive coating 20. Thus, the two conductors 6
and 20 are provided on different planes, and on opposite sides of
the PVB layer 5. When this circuit is driven, electromagnetic
energy is caused to couple with ice 18 on the exterior surface of
substrate 1. Again, this technique allows the impedance of the
circuit to be tuned so that only when ice is present then the
circuit becomes lossy and dissipates energy to the ice 18, and
otherwise the circuit resonates in certain example embodiments of
this invention. In certain alternatives of the FIG. 4 embodiments,
both conductors 6 and 20 may be of the continuous coating type
(e.g., of ITO or Ag).
While the invention has been described in connection with what is
presently considered to be the most practical and preferred
embodiment, it is to be understood that the invention is not to be
limited to the disclosed embodiment, but on the contrary, is
intended to cover various modifications and equivalent arrangements
included within the spirit and scope of the appended claims.
* * * * *